Gibberlings3 come to mind:
The Gibberlings Three Forums
Then there is Pocket Plane Group.
Apparently IWD2 is tough to mod, not as easy as Baldurs Gate 2. I had a go at patching Icewind Gate 2, it was hard going.
Icewind Gate 2 plays BG2 on the IWD2 game engine. See my topic in the BG2 part of the Bioware Social forum. Then there is the IWD2 part of the Boards of Magic forums:
Icewind Gate - Delta version